Hot-air furnace.



No. 673,397; Patented May 7, I90l. J. W. HORNSEY.

. HOT AIR FURNACE.

(Application filed Jan. 30, 1901., (No Model.) 8 Sheets-Sheet l.

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HOT AIR FURNACE.

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No. 673,397. Patented May 7, 19m. J. W. HURNSEY. HOT AIR FURNACE.-'

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a F K m wr M m Nrrnp TATES' PATENT JOHN W. HORNSEY, OF CLEVELAND, OHIO,ASSIGNOR TO CROWN DRYER COMPANY, OF SAME PLACE.

HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No. 673,397, dated May '7,1901.

Application filed January 30, 1901- Serial No. 45.3467. (No model.)

T at whom it may concern.-

Be it known that 1, JOHN W. HORNSEY, a citizen of the United States,residing at Cleveland, in the county of Ouyahoga and State of Ohio, haveinvented certain new and useful Improvements in Hot-Air Furnaces, ofwhich the following is a specification.

The improvement which. is claimed under this patent has for one objectthe heating of IO air for drying and heating purposes to a temperatureimpossible solely in metallic radiators. A further object of myinvention is the conversion of practically all the heat units of thefuel into pure hot air. Resulting from these objects other importantadvantages are obtained, and particularlyan economyimpossible in othersystems.

The following explanation will aid in a better understanding of theobjects of my invention and the manner in which it is rendered possibleto use metallic radiators in combination with a furnace and a heatextractor and radiator of heat-resisting material interposed between thefurnace and the metallic radiator for the heating of air in thin volumesto a high temperature and in which the products of combustion have atemperature impossible of use in direct contact with metallic walls. Thesame amount of fuel consumed at a temperature of, say, 1,000 Fahrenheitwould, ifconsumed in a temperature of 2,500 Fahrenheit, heat the same oreven a considerably larger volume of the gases of combustion to thistemperature of 2,500 as would be required in the case above stated toheat this same volume to 1,000". By the interposition of a heatextractor and radiator built of fire-resisting material between thefurnace and a metallic radiator I extract the heat from thetire-resisting structure and make use of it, so as to reduce thetemperature of the products of combustion passing through it from, say,2,500 to about 1,000", after which the fire products at the last-namedtemperature are caused to pass through a metallic radiator. From thisprocess it will be seen that the heat extracted from the products ofcombustion while passing through the fire-brick radiator and beingreduced from 2,500 to 1,000 is a clear gain as compared with othersystems, for the reason that no more coal is required to obtain thehigher temperature, and after this heat of 1,500 has been extractedthere remains the same volume of gases and at the same temperature fromwhich to extract the same amount of heat as in radiators of solelymetallic systems.

The high temperature requisite for perfect combustion is used to effectthe saving of from fifty to seventy-five per cent. of fuel. In obtainingthis result I employ in a single structure a heat extractor and radiatorhaving a capacity of high temperature but of low radiating capacity anda separate and independent radiator having a low temperature but a highradiating capacity, whereby the products from the furnace pass into andthrough the radiator of low radiating capacity ata temperature of 2,500and are caused to give up, say, 1,500 by radiation to air passing intoand through such radiator, while the remaining 1,000 of heat areutilized in the radiator of high radiating capacity to heat the air inits passage to the radiator of low radiating capacity. In this way myinvention 5 effects acomplete combustion of the fire products byproviding for a temperature required to effect such combustion, andafter extracting, say, 1,500 from this perfect combustion in heatingthin volumes of air there will still remain of this perfect combustionas much heat passing from the low to the high radiator as can beobtained by other systems.

The following description, read in connection with the accompanyingdrawings, will enable any one skilled in the art to which my inventionrelates to understand its nature and to practice it in the form in whichI prefer to employ it; but it will be understood that my invention isnot limited to the pre- 0 cise form and construction herein illustratedand described, as various modifications and changes may he made withoutexceeding the scope of the claims in which my invention is set out. 5

Referring to the drawings, Figure 1 represents in vertical section myimproved hotair furnace. Fig. 2 is a transverse section of the same.Fig. 3 is a horizontal section on the line a, a of Fig. 2, showing thecommunirco cation of the air-fines of the fire-resisting radiator withthe hot-air-delivering and the airstorage chambers, a pair of metallicradiators being shown in the air-storage chamber. Fig. 4 is a horizontalsection on the linebbof Fig. 1, showing a pair of base-fiues and theirtermination in the draft-stack. Fig. 5 is a horizontal section on theline 0 c of Fig. 1, showing the transverse walls, the cross-openingstherein, and the tire-flue passages formed thereby which open directlyinto the baseflues, which are shown in dotted lines and across which thesaid walls are built. Fig. 6 is a section through the flue-wall on theline (1 d of Fig. 5, showing one of the transverse walls andthecross-openings therein seen in Fig. 5, by which the fire-finesbetween said walls communicate with each other. Fig. 7 is a like sectionon the line e e of Fig. 5, showing one of the transverse fire-fines 19opening into the base-fines and the vertical fireflues opening into thesaid transverse line. Fig. 8 is a horizontal section on the line ff ofFigs. 1 and 7, showing in section the slab floor which covers thetransverse fire-fines which open into the base-fines and also thefloor-openings for the vertical fire-fines. Fig. 9 is a horizontalsection on the line 9 g of Fig. 1, showing one of the air-spaces betweenthe floor-slabs opening at the opposite walls of the fire-resistingradiator and the vertical fire-fines passing through openings in thefloor-slabs. Fig. 10 is a transverse section on the line h h of Fig. 9,showing the connection of the pair of metallic radiators with the pairof base-fines. Fig. 11 shows a group of builtup slabs and blocks. toillustrate the manner of forming the air-spaces and the fire-fluesof thefire-resisting, heat-extracting, and heatradiating structure which Iprefer to use and the direction of the air and fire through thestructure.

The fine structure is of fireq'esisting material and in tiers ofpassages, in which the air is heated in comparatively thin volumes. Itis interposed between the furnace and a separate and distinct metallicradiator, whereby I am enabled to use the products of combustion at atemperature of, say, 2,500 from a radiator of low capacity for heatingair in connection with a radiator wherein it would be impossible to usesuch high temperature. This flue structure is built up of fire-brick orslabs within a closureof thick walls 1, so as to form verticalfire-fiues and horizontal airspaces 2, through which the walls of thevertical fire-fines 3 pass in staggered relation between the floors 4,forming the air-spaces. The fire-flues are built up of fire-brick wallsupon the arches of base-fiues 5, into which they open, while at the topof the radiator the fire-fines open into a heat-diifusion chamber 6,which by a vertical flue 7 between the closure-walland the radiatorcommunicates with thefu-rnace 8, as in Fig. 2. The airspaces 2 areformed by the horizontal slab floors4, arranged in tiers, the spacesbetween each tier extending through the structure andopen byflue-openings 9 at the vertical ture.

. spaces.

closure-Wall into a hot-air chamber 10 and by flue-openings 11 into anair-storage chamber 12. .The slab floors are supported upon blocks 13,set at the corners of the vertical fireflues, whereby shallow fire-fines14 are formed between the slab floors 4 alternately with the air-spaces2 and into which shallow fiuesthe vertical fire-fines 3 open, Figs. 1and 2, whereby the fire products are caused to pass successively fromthe vertical fire-fines into the shallow hues and be diffused thereinbetween the floor-walls of the air-spaces, into which they give up heatby radiation, While the walls of the vertical fire-fines also give upheat by radiation into the air-spaces 2, so that the air entering thelatter from the storage-chamber 12 passes incontact with walls formingthe fiues through which the products of combustion pass at atemperatureof, say, 2,500 and passes therefrom into the hotair-delivering chamber10, havingabsorbed in such passage about 1,500 of su-chtempera- Stillremaining in this flue structure is a temperature of, say, 1,000, andthis I utilize for heating the air before it enters the flue structure,so that the air iscaused to pass therefrom at a temperature which it isimpracticable to obtain from any metallic radiatingsystem. In thisconstruction I prefer to have. the vertical depth of thefire-flues 3 andthe air-spaces 2, Fig. 1, about equal; but the horizontal fire-fines 14may beof considerably less depth the better to hold and difiuse the heatproducts in contact with the slab floors which form the top and bottomof the air- This construction of supporting the slab floors and formingthe fire-fines is best seen in Fig. 11, wherein the air-spaces and thefire-fines are formed by the same walls, the arrows 15 showing thecourse of the fire products and the arrows 16 the course of the air,Which in its passage absorbs the heat from the flue-walls. The fireproducts pass fromthe furnace into the heat-difiusion chamber 6, thencethrough all the descending fireflues 3, and around and between the wallswhich form the air-spaces into a base-flue, which extends from the wallat which the hot air is delivered from the flue structure to thedraft-stack, asin Fig. 1.

The heat-diffusion chamber is arched over the top of the flue structureor otherwise suitably formed, and therein concentrates the greatest heatfrom the furnace, so that the draft-stack has direct communication withthe'furnace through this heat-diffusion chamber and the hue structure.The base-fines have sufficient capacity to insure the proper draftthrough the line structure, and in this respect the fire-fines enteringthe base-fines are adapted to give free outlet. This construction isbest seen in Figs. 1, 5, 6, and 7, wherein are shown the first tier offire-fl.ues, which open into the base-fines. Upon the arches. of thebase-flues-are built the parallel transverse walls 17, which form piersby being intersected with openings 18, which open into IIO thefire-fines 19, formed between these transverse walls, and into thebase-fines, making the exit of the fire products free from the fluestructure. On these piers is laid the bottom slab floor, and the latteris laid in successive tiers upon the blocks 13 and on the tops of thevertical fire-flue walls.

Referring to the communication between the fire-fines and thebase-fiues, the construction by which such communication is effectedprovides, besides a full and free communication for the passage of thefire products from the flue structure, a firm foundation upon which toerect the structure, a uniform draft from all the fire-fines, andaffords a convenient means for cleaning the foundation-fines, to whichaccess is afforded through the basefiues. Especially is thisconstruction important by reason of the unobstructed space afforded bythe crossing of the base-fines by all the transverse flues 19, as seenin Fig. 7.

The air enters the hot Walled spaces from the chamber 12, which inclosesall the inlet wall-openings and which is preferably open at one side 20,Figs. 1 and 3, some distance from the flue-wall, so as to form thestoragechamber to allow an equal and uniform volume of air to pass intoall the air-heating spaces. This air-storage chamber forms the housingfor one or more metallic radiators 21, which may be of any suitableconstruction, but which I prefer to mount directly upon the base-finesand to use in the form of an inverted U, their ends opening into thebase-fines, so that the products of combustion leaving thefire-resisting radiator-say at 1,000 temperature-are caused to pass fromthe base-fine into and through these metallic radiators and from thenceback into the baseflues to the draft-stack 22, whereby the air in thestorage-chamber 12 is caused to pass over and around the walls of themetallic radiator and absorb therefrom heat not radiated from thefire-resisting flue structure to heat the air before it enters thelatter. For regulating the draft through the metallic radiator or fordiverting the draft therefrom directly to the draft-stack a pair ofvalves 23 and 24; is provided in the base-flue, one, 23, located betweenthe fire-resisting and the metal radiators and the other, 24:, betweenthe open ends of the metallic radiator.

By opening the valve 23 more or less and closing the valve 24 the volumeand the temperature of fire products passing into the metallic radiatorcan be regulated as may be found necessary to suit the conditions underwhich the furnace may be used.

By opening the valve between the open ends of the metallic radiator thefire products will be diverted from the metallic radiator and caused topass directly to the draft-stack. It will be noted that the products ofcombustion in passing through the metallic radiator are in anupWard-and-downward course and that the upper or over passage 25 thereinis of greater area than the vertical passages,

thereby supplying a larger radiating-surface at the point at which theproducts of combustion are partially retarded in their passage by reasonof the natural tendency of the heat units to ascend with greater freedomthan to descend.

The provision of the pair of base-fines and their relation to thefire-resisting structure are important to cause a uniform diffusion ofthe fire products through the fire-fines.

Since all of the fire-fines are in direct communication with each otherand with the furnace, the tendency of the fire products would be to seekthe most direct course in entering the fines, and therefore a greaterproportion of the fire products might be drawn into those fines of thestructure nearest the communication with the furnace. This would resultin the unequal heating of the fire-flue walls and the consequent unequalheating of the air in its passage through the structure. overcome thisunequal distribution of the fire products in their passage through thefine structure, the draft through the base-fines is controlled by avalve in each base-flue, located between the fine structure and thesource of the draft, so that the valve in one base-flue may be adjustedto give adilferent area in one base-flue from that of the other, andthis difference of flue area would result in an equal distribution ofthe draft throughout the flue structure, with the consequent uniformdiffusion of the fire products throughout said structure, and in thismanner the temperature of the air in its passage through the structureis rendered uniform at all parts of the air-passage of each tier. Bythese valves one of the base-fines may be entirely cutoff, if desired,and it will be noted that as these base-fines are parallel to each otherin the same horizontal plane and haveidentical communication with thefire-fines the cutting ofl of one will not affect in any way thefunction of the other, since the draft through all the fire-fines can beentirely directed into either of the base-fines.

It is also important to note that the combined area of the air-heatingstorage-chamber 12 around the walls of the metallic radiator is greaterthan the combined area of the wall-openings 11, through which the airpasses from the storage-chamber into the airheating spaces of thefire-resisting radiator. It is this construction which gives the storagecapacity to the air-inlet chamber, because the passage of the airtherefrom is somewhat retarded,and consequently is caused the better toabsorb the heat from the metallic radiator, so that the hot air fromthis storagechamber will avoid the danger of cracking the walls of thefire-resisting radiator. Another feature of the two radiators, one oflow radiating capacity and the other of high radiating capacity, is thatthe walls of the upper tiers of the air-spaces being the hottest aremore susceptible to injury from the admission of air at a lowtemperature; but the admission of air from the storage-chamber beingrelatively of the same proportionate temperature from its top to thebottom renders injury to the walls of the fire-brick reduced to aminimum. In Fig. 1 is seen a housing 26 for a suction-fan draft at theoutlet of the hot-air-s'upply chamber, whereby the air is drawn throughthe fire-resisting radiator from the air-storage chamber; but obviouslyan airfusion-chamber, so thatco'l'd air entering this flue at avalve-controlled opening 29 on the closure-wall of the fluestructure-over andoutside of the closure for the air-storage chamber isheated and delivered in'tothe hot-air chamber above-the air-spaces oftheflue structurer This crown-chamber is also heated from the heat fromthe body of the flue structure, so that the temperature of the airdelivered from the flue structure may be regulated from the chamber" ofthe metallic" radiators and from the flue over the heat-difiusionchamber, giving thereby a control of the temperaturesu-ited for dryingor for heating.-

In some instances an absolutely uniform temperature is essential, and insuch cases provision may be made for'adjusting the valve 29automatically, and for which a thermostat or other suitable means may beused.

In Fig; 3 twofurnaces are provided side by side, both communicating withthe heat-diffusion chamber by separate flues 7 7; but ohviously one ormore furnaces may be used, as may be deemed advisable. In like mannerone or more base-fines may be used with metallic radiators 12, which areset in the airstorage chamber, one in independent communication witheach base-flue.

If desired, provision may be made for regulating the area of theair-inlet openings 11 of the fire-brick radiator to'regulate the volumeof air passing through it. Provision may be also made whereby access maybe had for cleaning all the fire-fiuesandother parts of furnace.Provision may also be made for access to clean the upper part of themetallic radiator at 30 in Fig. 1'.

I haveshown and describeda fire-resisting flue structure as constructedwith tiers of horizontal air-spaces and vertical fire-fines; but it isobvious that the number of tiers may vary from one to any desirednumber, as conditions may require,- and without changing the functionsand relations of the coacting parts in the storing, heating, anddelivering of the air or the results derived from the extraction byradiation of the heat from the products of combustion in their passagethrough the high and low temperature radiators.

Now looking at my present invention in its broad conception thefollowing will show a result which is of primary importance in myinvention.

In the absorption of water from the material in the operation of dryingit is well known that the capacity of air for the absorption of i waterincreases approximately four times as rapidly as the temperatureas, forinstance, an increase of, say, fifty percent. in the temperature of theair as thed ryi'ng medium will accomplish the result of increasing theabsorption capacity about two hun'd red per cent. Therefore, inasmuch aswith my present invention I am enabled toproduce hightly-h'eated airbeyond the temperature of other systems, it is, as a concomitant result,possible for me to produce air with a very largely inj creased capacityfor the ab'sorption' of water, 5 whereby the same volume of air iscapable of F performing much more work th'auis'possible iwith othersystems and in which the mate- 'j' rial to be dried will withstandwithout injury 5 this high temperature.

Now applying these 'well-known principles to my present inven- 1 tion itwill be seen that the provision of regulating the temperature of the airin the hotair-supply chamber and the provision whereby the fire-draft isregulated become important factors in adapting the temperature of theair as regards its capacity to absorb water to the material to be dried.In this cooperating regulation of the temperature of the air and ofthefire-draft the two regulating devices coactthat is, the valvecontrolling thecold-air flue'and thevalve'co'nt'rolling the basedraft-flue. In this cooperation by adjusting the valve of thecold-airflue as may bede'sir'ed the temperature of the-air at the point ofdelivery is increased or diminished, and by adjusting or partiallyclosing the valve 23 in the base draft-flue the'fireproducts are causedto be retarded in theirpassage through j the flue-structure, therebymaterially increasiing their temperature in the flue structure, ?with aconsequent increase in the tempera- 1 tureofthe walls of the air-spaces,and conseia quently increasing the temperatu reof the air in its passagethrough these spaces to thepoint of delivery.

The location of the'cold-air flueabove the flue structureis important,because the temperatureof air at the point'of delivery from thiscold-air flue into the hot-air-supply chamber being considerably lessthan that of the 1 hot air at the point of delivery from theairpassagesof the flue structure thetendencyv of the air issuing from the hot-airpassages into the supply-chamber is therefore upward,

While that of the air'passing from the coldair flue into thehot-air-supply chamber is downward.

These opposite directions of air courses at different temperaturesefiects a complete commingling of the air in this chamher, so that it isdelivered continuously therefrom at a uniform tem peratu re.

In starting the fire the metallic radiator may be cut out of the draftand the air-inlet openings of the flue structure may be closed in anymanner until the flue structure shall have obtained a working heat.

I do not in the Letters Patent to be issued on this application claimthe herein-described process for heating air, nor for treating theproducts of combustion in the heating of air, nor the processes hereindescribed in which the heating of air and the treatment of the productsof combustion are employed and regulated to regulate the temperature ofthe air at the point of delivery, as such processes constitute thesubject-matter of claim in an application filed by me of even dateherewith for an improvement in the process of heating air.

I claim 1. In an air-heating furnace and in combination, a fluestructure of fire-resisting material, forming an air space or spaces andfire-flues, an air-storage chamber and a hotair-supply chamber onopposite sides of said flue structure, both chambers havingcommunication with said air-flue space and inclosing the opposite endsof said spaces, a furnace having communication with the fireflues, and ametallic radiator located in the air-storage chamber, the fire-resistingflue structure being interposed between the furnace and the metallicradiator, a base draftflue having communication with the fire-fines andwith the metallic radiator, and a draftstack.

2. In an air-heating furnace and in combination, a flue structure offire-resisting material forming tiers of air-spaces and fire-fines, anair-storage chamber and a hot-air-supply chamber on opposite sides ofsaid flue structure, both chambers having communication with saidair-spaces, and inclosing the opposite ends of said spaces, a furnaceand a heatdiifusion chamber in communication with the latter and withthe inlet-openings of the fireflues, a cold-air flue above theheat-diffusion chamber, opening at one end into the hot-airsupplychamber and at its other end to the outer air by a valve-controlledinlet, a base draft-flue in communication with the fireflues and adraft-stack for the purpose stated.

3. In an air-heating furnace and in combination, a flue structure offire-resisting walls for'ming tiers of air-spaces and fire-fines, anair-storage chamber and a hot-air-supply chamber on opposite sides ofsaid flue structure, both chambers having communication with saidair-spaces and inclosing the opposite ends of said spaces, a furnacehaving communication with the fire-flues, and a metallic radiatorlocated in the air-storage chamher, the flue structure being interposedbetween the furnace and the metallic radiator, a base draft-flue havingcommunication with all the fire-fines and by openings with the metallicradiator, a draft-stack, and a pair of valves located in the base-flueone between the fire-brick flue structure and the metallic radiator andthe other between the openings which open from the metallic radiatorinto the base-flue for the purpose stated.

4E. In an air-heating furnace and in co inbination, a flue structure offire-resisting Walls forming tiers of air-spaces and fire-flues, anair-storage chamber and a hot-air-supply chamber on opposite sides ofsaid flue structure, both chambers having communication with saidair-spaces and inclosing the opposite ends of said spaces, a furnacehaving communication with the fire-flues at the top of the linestructure, a base draft-flue having communication with all thefire-fines, a metallic radiator upon the base-flue in the air-storagechamber, and communicating by openings with the base-flue and having itsover top part of larger area than its baseflue openings, adraft-regulating valve in the base-flue between the fine structure andmetallic radiator, means for cutting out the metallic radiator from thedraft-passage, and a draft-stack.

5. In an air-heating furnace and in combination, a flue structure offire-resisting walls forming tiers of air-spaces open at their oppositeends in the closu re-Walls, and fire-fines, an air-storage chamber and ahot-airsupply chamber on opposite sides of said flue structure inclosingall the inlet and outlet openings of said air-spaces, a furnace havingcommunication with the fire-fines at the top of the flue structure, abase draft-flue having communication with all the fire-flues, a metallicradiator upon the base-flue in the airstorage chamber and communicatingby openings with the base-flue, the total area of the air-heatingchamber around the walls of the metallic radiator being greater than thetotal area of the wall-openings of the air-spaces, a draft-stack, andmeans whereby the draft is regulated in the base-flue.

6. In an air-heating furnace and in combination, a flue structure offire-resisting material constructed with Walls forming fireflues andair-spaces heated by the fire-flue walls, a heat-diffusion chamber abovethe flue structure and in communication with the fire-fines thereof, ahot-air-supply chamber in communication with the air-spaces in the fluestructure, a valve-controlled cold-air flue supplementing theheat-diffusion chamber, and opening into the hot-air-supply chamber, anda furnace in communication with the heat-diffusion chamber.

7. In an air-heating furnace and in combination, a fine structure offire-resisting material constructed to form fire-flues and tiers ofair-spaces heated by the fire-flue walls, a hot-air-supply chamber onone side of the flue structure, a valve-controlled cold-air flue,

IIO

the flue-structure air-s paces and the cold-air flue opening into thehot-air-supply chamber at one and the same side wall of the fluestructure, and the air-spaces and the cold-air flue opening at the otherside wall of the flue structure, and a furnace in communication with thefire-flues.

8. In an air-heating furnace and in combination, a flue structure offire-resisting material constructed to form fire-flues and tiers ofair-spaces heated by the fire-flue walls, a furnace in communicationwith the tire-flues, a pair of horizontal base draft-flu es each havingcommunication wit-h the fire-flues,a source of draft, and a valvecontrolling each baseflue, whereby a uniform diffusion of the fireproducts is obtained through the flue structure.

9. In an air-heating furnace and in combination, a flue structure offire-resisting material constructed to form fire-fines and tiers ofair-spaces heated by the fire-flue walls, a furnace in communicationwith the entrance of all the fire-fines, a pair of base draft-fines eachhaving identical communication with the fire-fines and with the sourceof draft, and a valve in each base-flue between the flue structure andthe source of draft whereby the draft area of one of said base-flues maybe regulated for effecting an equal distribution of the draft throughthe flue structure, or to cut it off Without affecting the function ofthe other base-flue.

10. In an air-heating furnace and in combination, a fiue structure offire-resisting material forming tiers of air-passages opening at theopposite side walls, and fire-fines, an air-storage chamber and ahot-air-supply chamber on opposite sides of said flue structureinclosing all the inlet and outlet openings of said air-spaces, afurnace having communication with the fire-fines at the top of the fluestructure, a valve-controlled cold-air flue above the inlet ends of thefire-flues, a metallic radiator in the air-storage chamber, meanswhereby it is caused to have communication with the outlet ends of thefire-flues, and means whereby such communication is controlled, as ameans for controlling the temperature of the air delivered from thehot-air chamber.

11. In an air-heating furnace and in combination, a flue structure offire-resisting material forming tiers of air-spaces opening at theopposite side walls, and fire-fines, an airstorage chamber and ahot-air-supply chamber on opposite sides of said flue structureinclosing all the inlet and the outlet open ings of said air-spaces, afurnace having communication with the fire-flues at the top of the finestructure, a metallic radiator in the air-storage chamber and meanswhereby said metallic radiator is caused to have communication with theoutlet ends of the fire-flues, the admission of air from thestorage-chamber into the said air-fines being relatively of the sameproportionate temperature from the top to the bottom tiers of saidair-spaces to prevent injury to the flue-structure walls at which theproducts of combustion enter at their highest temperature.

12. In an air-heating furnace and in combination, a flue structure offire-resisting material forming tiers of air-spaces opening at theopposite structure walls, and firefiues, a hot-air-supply chamberinclosing all the outlet-openings of said air-spaces, afurnace havingcommunication with the flre-flues, a baseflue having communication withall the fireflues, a metallic radiator upon the base-flue andcommunicating by openings with the base-flue, and means whereby thedraft may be directed through said radiator.

13. In an air-heating furnace and in combination,a fluestructure offire-resisting walls forming tiers of air-spaces and fire-flues,afurnace in com in un'ication with said fire-fines, a pair of basedraft-fines, a multiple of transverse walls forming flues each crossingand opening into thebase-flues and into which all the fire-fluesopen,the said transverse Walls being built up in piers 17 formingcross-openings 18 which connect the flue-spaces 19' on each side of saidtransverse walls, whereby a full and free communication-for the fireproducts is established between the fire-flues and the base-fines.

14. In an air-heating furnace andin combination,afiue structure offire-resisting walls constructed toform tiers of air-spaces andfireflues, a furnace in communication with said fire-fines, a multipleof transverse walls 17 forming flues 19 each crossing the base-fines andinto all of which transverse fiuesthe fireflues open, and a draft-stack,the said trans verse flues extending between the structurewalls andthesaid base-fines opening their full width into the transverse finesand meeting in their full area into thedraft-stack.

15'. In an air-heating furnace and in combination, a fine structure offire-resisting walls forming tiers of air-spaces and fil'6*fil168,ahot-air-supply chamber inclosing the outletopenings of the air-spaces,a furnacein communication with the inlet-openings of the firefiues, acold-air flue above the flue structure opening into the hot-air-supplychamber and to the outer air by'a valve-controlled inlet, a basedraft-flue in communication with the fire-fines, and a valve in thebase-flue for regulating the draft, whereby the temperature of the airis regulated at the point of delivery on one side of the flue structureand the firedraft is regulated at its other side with the consequentresult that by the coacti-ng'fune tions of these valved passages controlis had over the temperature of the air at the point of delivery, whilecontrol is had over the temperature of the heat products by retardingLII terial constructed to form fire-fines and tiers of air-spaces heatedby the fire-fines, a furnace in communication with the fire-fines, apair of horizontal base draft-fines each having communication with thefire-fines, a pair of metallic radiators in separate communication withthe base draft-fines, a pair of valves arranged in each base draft-fluewhereby to control the communication of the latter and of the metallicradiator with the fire-Hues, a source of draft, whereby a uniformdiffusion of the fire products is obtained through the flue structure inthe use of one or both of the base draft-fines.

1.7. In an air-heating furnace and in combination, a flue structure offire-resisting walls constructed to form fire-fines and tiers ofairspaces heated by the fire-fines, a furnace in communication with thefire-flues, a pair of horizontal base-fines having identicalcommunication with the fire-flues and with the source of draft, a pairof metallic radiators having identical separate communication with thebase-fines, a pair of valves having identical arrangement in eachbase-flue and relation to its metallic radiator, whereby the cutting outof one flue from the draft will not affect the function of the other.

18. In an air-heating furnace and in combination,a flue structure offire-resisting walls constructed to form fire-Hues and tiers ofairpassages heated by the fire-fines, a furnace in communication withthe fire-fines, a baseflue having communication with said flues and thesource of draft, a heat-diffusion chamber above the flue structurehaving communication with the furnace, a cold-air flue above theheat-diffusion chamber and a hotair-supply chamber into which the tiersof airpassages and the cold-air flue open, and a source of suction-draftfor the hot-air chamber, whereby to effect the commingling of airvolumes of different temperatures in the way and for the purpose stated.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN W. HORNSEY.

Witnesses:

A. ROLAND JOHNSON, GUY I-I. JOHNSON.

